Tobacco sheet forming apparatus



Aug. 25, 1964 R. c. GElTZ ETAL TOBACCO SHEET FORMING APPARATUS '7Sheets- Sheet 1 Filed Aug. 9, 1960 INVENTORS.

ROBERT CHARLES ean'z ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARDLEE ATTORNEY Aug. 25, 1964 Filed Aug. 9, 1960 7 Sheets-Sheet 2 1 P59 77Fl 6.4 9D I I III l l 90 H: \gr.

' l 'IIIl/IIE' m4 88 82 I r- A 7 \02\E :V I J/ 2 INVENTORS.

ROBERT CHARLES GEITZ ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARDLEE L-/\ ATTORN EY Aug. 25, 1964 R. c. GEITZ ETAL TOBACCO SHEETFORMINGAPPARATUS '7 Sheets-Sheet 5 Filed Aug. 9, 1960 ENVEE' -LTORSLROBERT CHARLES GEITZ ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARDLEE ATTORNEY Aug. 25, 1964 R. c. GElTZ ,ETAL

TOBACCO SHEET FORMING APPARATUS '7 Sheets-Sheet 4 Filed Aug. 9, 1960FIG.7-

INVENTORS.

ROBERT CHARLES GEITZ ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARDLEE ATTORR EY.

Aug. 25, 1964 R. c. GEITZ ETAL TOBACCO SHEET FORMING APPARATUS 7Sheets-Sheet 5 Filed Aug. 9, 1960 2 mm E s B E L m Wu C T R E B O RALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE ATTORN EY iE nINVENTORS.

ROBERT CHARLES GEITZ ALBERTO ISLAS 7 Sheets-Sheet 6 JOHN EDWARD LEEJOSEPH BRENDAN FARRELL R. C. GElTZ ETAL TOBACCO SHEET FORMING APPARATUSF l G Aug. 25, 1964 Filed Aug. 9, 1960 ATTORN EY Aug. 25, 1964 R. c.GEITZ ETAL 3,145,716

TOBACCO SHEET FORMING APPARATUS Filed Aug. 9, 1960 7 Sheets-Sheet 7INVENTORS.

ROBERT CHARLES serrz ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARDLEE FIG.

United States Patent 3,145,716 TDBACCO SHEET FOG APPARATUS RobertCharles Geitz, Darien, Conn., Alberto Islas,

Mexico City, Mexico, and Joseph Brendan Farrell,

Westport, and John Edward Lee, Byram, Conn.,

assignors to American Machine & Foundry Company,

a corporation of New Jersey Filed Aug. 9, 1960, Ser. No. 55,106 16Claims. (Cl. 131133) This invention relates to an improved process andapparatus for forming a continuous self-sustainable web or sheet fromparticulated material. In a narrower aspect, this invention relates totobacco sheet, and to apparatus and processes for forming tobacco sheet.

The broader applications of the invention which relate generally to theformation of a continuous web of material from finely particulatedsubstances will become apparent in describing the invention hereinbelow.For the purpose of providing in greater detail the advantages affordedhereby, however, the invention will be described in connection with thepreparation of a self-supporting tobacco sheet prepared from finelydivided tobacco or tobacco dust. The useful application of the apparatusand process forming the basis of the present invention to the formationof continuous sheeting from other finely particulated material such aswood, leather, abrasive particles, flour or other edible foodstuffs andthe like with desirable obvious modifications will be apparent to thoseskilled in the art.

An object of the present invention is to provide a very substantiallyimproved method and apparatus for the continuous formation of flexibleself-supporting web from particulated or finely subdivided materials inwhich the flavor, aroma, color or other desired characteristics of thematerial are retained.

A further object of this invention is to provide an apparatus whichforms tobacco sheet of greater uniformity in thickness and moreaccurately controlled moisture content.

Another object of this invention is to provide an applicator to applybinding material in tobacco sheet formation in a fluid or slurry formwith a more uniform distribution.

Still another object of this invention is to provide an applicator toapply binding material which is self-cleaning and non-clogging.

Yet another object of this invention is to provide, in an apparatus forthe production of tobacco sheet, an endless steel belt extending abouttwo large pulleys with apparatus to automatically correct for lateraltravel or wandering of the belt on the pulleys.

A further object of this invention is to provide, in apparatus forforming tobacco sheet having an endless steel belt, drying apparatus andtobacco sheet conditioning apparatus which will automatically track ormove with the belt to compensate for lateral wandering of the belt.

A still further object of this invention is to provide apparatus for themore even distribution of dry dust in the formation of tobacco sheet.

An additional object of this invention is to provide in a complete unit,a more compact machine for the production of sheet tobacco.

Many other objects, advantages and features of invention reside in theparticular construction, combination and arrangement of parts involvedin the embodiment of the invention and its practice as will beunderstood from the following description and accompanying drawingwhere- FIG. 1 is an isometric illustration of the entire assembly of thevarious components making up the sheet forming plant;

FIG. 2 is a front elevation of the water applicator;

FIG. 3 is a section taken on line 33 of FIG. 2;

FIG. 4 is a view, partially in section, taken on line 44 of FIG. 3;

FIG. 5 is a front elevation of the dust feeding and applying apparatus;

FIG. 6 is a side view, partly in section, of the dust feeding andapplying apparatus;

FIGS. 7 and 8 are front elevations of the steam box drying apparatuswith .the belt tracking mechanism;

FIG. 9 is a side elevation of the base web applicator;

FIG. 10 is an end view of the major base web applicator components;

FIG. 11 is a front view of the sheet conditioner;

FIG. 12 is a side elevation, partly in section, of the sheetconditioner;

FIGS. 13 and 14 are schematic front elevations of the continuousautomatic belt tracking system;

FIG. 15 is a side elevation of the support and guide structure of thecorrecting roller of the belt tracking sys tem; and

FIG. 16 is a view taken on line 16-16 of FIG. 15.

Referring to the drawings in detail, the sheet forming plant illustratedin FIG. 1 consists of an endless stainless steel belt or conveyor 20which is supported and driven at a constant speed by means of a pair ofpulleys or drums 22 and 24 mounted on shafts 26 and 28 respectively. Thebelt 20 may be from 8 to 86 inches wide and, generally, from .016 to.050 inch thick and may be of half-hard, Type 301 Stainless Steel. Thediameter of pulleys 22 and 24 should be at least one thousand times thethickness of belt 20. Shafts 26 and 28 are supported by suitableadjustable bearings of a main frame (not shown) of the machine. At thefront and above the belt conveyor 20 is mounted a water applicator 30which deposits a film of water on the top surface of conveyor belt 20.Also above the conveyor belt 20 a short distance from the waterapplicator 30, there is mounted a dust feeder 32 for the purpose oflaying a layer of dust onto the film of water carried by the movingconveyor belt 20. After the layer of dust is applied on the film ofwater, the belt conveyor 20 passes through a suitable dryer 34 and then,upon emerging, passes beneath a base web applicator 36 which deposits alayer of suitable binder material onto the dried sheet material carriedby the conveyor belt. After the binder material has been deposited ontothe sheet, the belt conveyor passes beneath a second dust feeder 38where another layer of dust is applied on top of the above mentionedbinder material web. The entire sheet, which has been formed on the beltconveyor 20, is then carried through a suitable drying apparatus 40where the sheet is thoroughly dried. The belt conveyor 20, afteremerging from drying apparatus 40, carries the dried sheet through aconditioning apparatus 42 which supplies a controlled amount of moistureto the sheet to facilitate the lifting of the sheet from the conveyorbelt and to make possible the proper cutting and handling of thefinished product. The lifting of the sheet from the conveyor belt 20 isdone at the end of the conveyor by a doctor knife 44 and the finishedsheet is then guided into a lawn mower type cutting apparatus 46 wherethe sheet is cut into pieces of a desired size.

The water applicator 30, shown in FIG. 1 and illustrated in detail inFIGS. 2, 3 and 4, consists of a rubber roller or rubber covered roller50 which is mounted on a horizontal shaft 52 rotably supported at eachend by a bearing 54 each of which is secured to a vertical plate 56.Each plate 56 is slidably held in a vertical track 58 formed by suitablerails 59 secured to the main frame 60 of the machine. The lower end ofeach vertical plate 56 is pivotally connected with the upper end of apiston rod 62 which projects from the upper end of a vertical aircylinder 64 secured to the main frame 60 of the machine. Shaft 52, whichcarries the roller 50, is continuously rotated by a pulley 66 by meansof a belt 68 which is connected to a suitable variable speed drive (notshown). The bottom portion of each air cylinder 64 is connected by meansof a tube 70 to a suitable hand operated air valve (not shown) by meansof which air pressure may be introduced into each cylinder to effect anupward motion of the piston within it which in turn causes an upwardmotion of the vertical plates 56 and the bearing brackets 54 mountedthereon. Since the bearing brackets 54 support the shaft 52 on which theroller 50 is mounted, the roller 50 may be raised above and away frombelt to a desirable degree when it is not in operation. Above the top ofroller 50 is suspended a suitably shaped skimming knife 72, as shown inFIGS. 2 and 3, which is provided at each end with an extension 74 bymeans of which the knife 72 is supported by a pair of adjustablesupporting studs 76 each of which projects upwardly from the lower legof a U-shaped bracket 78. A pair of compression springs 77 confinedbetween the upper edges of extensions 74 and the upper legs of bracket78 provides a resilient mounting and permits the adjusting of theskimming knife 72. Each bracket 78 is secured to a vertical plate 56 sothat the raising and lowering of roller 50 does not effect the settingof the skimming knife 72 in its relation to roller 50 because knife 72moves with the roller assembly. To each end of the skimming knife 72there is secured a vertical plate 80' the lower portion of which looselycontacts an end of the roller 50 as illustrated in FIGS. 2 and 3.Between the plates 80 and roller 50 there is secured a U-shaped troughS2 to the front side of which is suitably mounted a rubber plate 84having a lower beveled edge which contacts the surface of the roller 50along its entire length. Thus plate 84, plates 80 and skimming knife 72form a trough 86 across the top of roller 50 as shown in FIG. 3. Intrough 86 there is suspended a horizontal tube 88 containing a pluralityof suitable holes in its bottom portion so that any water supplied bymeans of the connected tube 90 runs into the trough 86. The tube 90 isconnected to a suitable supply of water (not shown). In order to preventthe water supplied to trough 86 from seeping out between the verticalplate 80 and the ends of roller 50, each plate 80 is provided with anarcuate channel 92 in which is loosely inserted an arcuate sealingmember 94 made of plastic, nylon or similar material. Each plate 80carries a pair of compression springs 98 in suitable indentations 96which press the sealing member 94 against the ends of the rotatingroller 50 and assure a tight seal at the ends of the trough 86. Eachsealing member 94 is provided with a suitable stud 100 which looselyprotrudes through an aperture in its adjacent end plate 80 to serve as aretainer of the member 94 in channel 92. The trough 82 is provided witha drain pipe 102 to serve as an overflow to prevent the water level intrough 86 from reaching an undesirable height.

As illustrated in FIG. 3, the lower edge of the skimming knife 72 isaccurately set with a clearance from the roller 50 to permit the latterto carry a film of water W of predetermined thickness to the moving beltconveyor 20 where the film of water, by means of a wiping action of theroller 50 against conveyor belt 20, is transferred to it.

It should be pointed out that the air cylinders 64 are double acting sothat they maybe used to apply uniform nip pressure in the downwarddirection, as well as lifting the roller from the belt in the upwarddirection.

This method ofapplying water to the belt is very substantially superiorto the spray techniques heretofore known and employed for this purpose.The water applicator of the present invention:

(a) provides a much more uniform coating;

([1) permits the thickness of water layer to be closely controlled;

(0) requires much less space, reducing the conveyor lengthsubstantially;

(d) eliminates the mist nuisance;

(e) is unaffected by non-uniformities or variations in thickness in thecoated belt, the same quantity of material being laid down regardless ofthese variations.

It should be noted that the coating of a moving belt with a thin,uniform film of low viscosity fluid, such as water, is an extremelydifficult problem. Attempts to employ other methods of application suchas wiping the belt with saturated sponges, spraying with a brush, knifecoating, overflowing weirs, etc. have been unsuccessful orunsatisfactory.

The conveyor belt 20 then carries the film of water beneath the firstdust feeder 32, as shown in FIG. 1, where a layer of tobacco dust D isdeposited onto the film of water W. The dust feeder 32, illustrated indetail in FIGS. 5 and 6, consists of a closed hopper 104 which, by meansof a duct 106, is connected to a suitable tobacco dust supply (notshown). Across the center portion of the hopper 104 runs a continuouslydriven agitator shaft 108 which is provided with a plurality ofhook-shaped agitator fingers 110 which prevent the formation of lumpsand effect the flufiing of the tobacco dust in the hopper 104. It willbe apparent that the fluffing agitator may be eliminated withoutdeparting from the invention when employing a feed which does not have atendency to agglomerate into lumps. The hopper 104 is mounted on asuitable frame housing 112. The bottom of hopper 104 is provided with anopening 114 into which projects a portion of a knurled roller 116. Thelower front portion of hopper 104 is also provided with an adjustablegate plate 118 pivotally suspended from a horizontal rod 120 which issecured in suitable lugs which are formed integrally with frame housing112. The lower end of the gate plate 118 forms a tangent with theknurled roller 116 and the opening or space desired between the roller116 and gate plate 118 may be set by means of a stop screw 122 carriedby the gate plate 118 and kept in engagement with the end plates of thehopper by a suitable compression spring 124 confined between the innerwall of a frame bracket 126 and the front side of gate plate 118. Thespace which is adjustably set between the knurled roller 116 and thegate plate 118 controls the amount of tobacco dust carried out of thehopper 114 by the knurled roller 116.

The knurled roller 116 is mounted on a horizontal shaft 128 which iscontinuously driven through suitable sprockets and a chain by means of avariable speed drive unit 130 mounted on the top of the frame housing112. The shaft 128 is rotatably supported by a U-shaped bearing bracket132 mounted on a pair of spaced studs 134 which in turn are adjustablysecured in a pair of suitable lugs 136 which form part of the framehousing 112. The adjustability of the knurled roller 116 is essentialfor obtaining the desired penetration compensating for the wear of thebristles of a cylindrical rotating brush 138 which engages with therotating knurled roller 116. Brush 138 is mounted on a horizontal shaft140 rotatably supported by suitable bearings in the frame housing 112.Shaft 140 has secured to it a pulley 142 which is driven by a belt 144and a pulley 146 mounted on a motor shaft 148 of a motor 150 mounted onthe lower portion of the frame housing 112. The rotary brush 138 isemployed for the purpose of brushing the controlled amount of tobaccodust carried out of the hopper 104 by means of the rotating knurledroller 116 off the roller 116 and throwing it onto the water film Wcarried by the conveyor belt 20. This method of dust feeding has adecided advantage over systems heretofore employed of blowing dust ontothe conveyor belt in that it eliminates the conveying of a the dust in ahigh velocity air stream while providing adequate penetration of thewater or adhesive layer. This apparatus employed by the presentinvention applies the dust by centrifugal force through the air onto thewater film on the moving conveyor. The outer periphery of the brush hasa surface speed of 300 to 10,000 f.p.m. and preferably about 4,000 to6,000 f.p.m. This relatively high velocity of the brush provides theessential effectiveness of this novel feeder, since it accelerates thedust particles to a velocity which gives comparatively excellentpenetration of the film being coated. Beneath both edges of the conveyorbelt 20 are resiliently mounted a pair of troughs 152 which extendthrough the entire length of the frame housing 112. The troughs 152 areemployed for the purpose of collecting tobacco dust which is showeredbeyond the edges of belt 20. Each trough 152 is provided with a suitablevibrator 154 which moves dry dust forward to a suction funnel 156mounted on the outside of housing 112. Since the suction funnel 156extends transversely over the entire width of the conveyor belt 20, itwill also pick up any loose dust which was not absorbed or held by thewater film on the belt. The top portion of funnel 156 is connected by atube 158 to a suitable suction system and dust collector (not shown). Tokeep the dust collected in the troughs 152. dry and free flowing, eachtrough 152 is provided with a suitable heating element 160. A butterflyvalve 162 in suction tube 153 controls the amount of suction with adesired range. In order to maintain a constant level of the dust in thehopper 104 to assure uniform dust feeding, the hopper is provided with aconventional rotary valve (not shown) in the dust supply system to whichhopper 104 is connected by tube 106. When the dust in the hopper reachesa predetermined level, the sensor 164 causes the rotary valve in thesupply line to close and, when dust is needed in the hopper, the sensor164 efiects the opening of the rotary valve. A conventional vibratorunit 166 is secured to one of the outer walls of the hopper 104 toassure a free flowing movement of tobacco dust within the hopper 104. Inorder to expel dampness from the dust feeder 32 which may lead tolumping and clogging of the tobacco dust, a hot air pipe 168 mayprotrude through the frame housing 112 in a suitable manner. Inside theframe housing 112 there is also adjustably mounted a suitably shapeddeflector plate 170 which keeps the dust stream thrown onto the conveyorbelt within a predetermined area.

This technique of relatively high speed operation i.e., greater thanabout 500 feet per minute, is also much superior to the blowing methodsbecause it is unnecessary to circulate a great excess of dust. Thepercentage of dust deposited by the high speed brush application of theinvention is very much greater than that deposited by the blowing methodand in fact approaches 80% or more. Furthermore, we have found that bythe blowing technique it is impossible to control the amount of dustdeposited whereas with the high speed brush feeder the amount of dustdeposited can be increased or decreased at will, by correspondinglyincreasing or decreasing the speed of the knurled feed roll.

It should also be noted that the high speed brush dust feeder of theinvention differs from previously disclosed brush feeders in that ourbrush is specifically designed and required to operate at relativelyhigh speed (i.e., a surface speed greater than 500 feet per minute andpreferably in the range of 2,000 to 10,000 feet per minute) so as toimpel and impart to the dust a high kinetic velocity; this velocity isconsidered generally about 60% to 95% of the brush surface velocity.Although the use of brush feeders has been considered heretofore suchdust feeders operate at very low speeds and virtually allow the dust tofall by gravity. We have discovered a suprisingly eflfective filmpenetration and advantageous product is obtainable by use of the highspeed brush herein described.

It will be apparent that the use of this high speed brush dust feeder isnot necessarily limited to the manufacture of tobacco sheet but can beused to coat any moving surface with a dry powdered material, especiallywhere some penetration of the surface being coated is required. Otherexamples of its use would be the prep aration of abrasive paper or clothby depositing abrasive powder on moving webs of paper or cloth. As usedherein the term dust connotes material particles sizes generally below 2mesh and preferably in the range of 30-325 U.S. standard mesh.

The dust covered water film is carried by the conveyor belt 20 from thedust feeder 32 into the dryer 34 as shown in FIG. 1. Dryer 34 consistsof a housing 172 in which is moveably mounted a self-aligning steam box174. The dryer 34, illustrated in detail in FIGS. 7 and 8, issubstantially of the same construction as the one illustrated anddescribed in the patent application for Steam Drying Method andApparatus, Ser. No. 814,762 filed on May 21, 1959, now abandoned. Steambox 174 is mounted on a pair of spaced transverse bars 176, each ofwhich is provided at their outer ends with a pair of downwardlyprojecting forked bearing brackets 178. Each bracket 178 rotatablysupports a horizontal shaft 180 on which is mounted a pair of groovedwheels 182. Each pair of wheels 182 supporting each transverse bar 176rides upon a transverse track 184 each of which is supported and securedto a cross beam 186 which, in turn, is mounted on a pair of longitudinalframe members 188. By supporting the steam box 174 on wheels riding upontransverse tracks, the steam box may be moved freely in a lateraldirection to follow any lateral travel of the conveyor belt 20 whichforms the moving cover for the steam box. A constant alignment of thesteam box with the conveyor belt keeps the steam and vapor loss at aminimum. This alignment is accomplished by means of a position indicatorarm 190 which is pivotally mounted to contact and engage with its freeend one edge of the endless conveyor 20 as illustrated in FIGS. 7 and 8.Arm 190 projects from and actuates a position transmitter 192 which, bymeans of a tube 194, is connected to a horizontal air cylinder 196mounted by means of a suitable bracket 198 on a longitudinal framemember 188. The air cylinder 196 is provided with a piston (not shown)which, in turn, is connected with a piston rod 200 having a free endwhich projects from the cylinder 196 and is pivotally connected with aforked lug 202 which is formed integrally with and projects from abracket 204 mounted on the side of the steam box 174. Since theindicator arm 190 is in constant contact with the side edge of themoving conveyor band 20, any lateral movement of the latter causes acorresponding movement of the indicator arm 190 which, in turn, actuatesa valve within the position transmitter 192 which transmits movements bymeans of the tube 194 to the air cylinder 196 to move piston rod 200 inor out. Since the end of the piston rod 200 is connected to the steambox 174, the latter precisely follows any lateral movement of theconveyor 20 and remains in alignment with it at all times. For any givenposition of the indicator arm there is a particular air signal to theair cylinder which through a closed loop feedback system provides inturn a particular position of the piston and its connections. Both theair cylinder 196 and the position indicator 192 are standardconventional pieces of equipment.

The steam box 174 is provided with transverse tubes (not shown) whichare connected to each other by suitable pipes in the same manner asdescribed and illustrated in the above mentioned pending patentapplication Ser. No. 814,762. The pipes within the steam box areconnected to a source of steam (not shown). The transverse tubes withinthe steam box 174 are provided with a plurality of spaced jets ornozzles for directing the steam towards the lower side of the passing296 which are mounted on the longitudinal frame members 298 of themachine. The cooling box 290 is the exact width of the belt 20 and iskept in constant alignment with belt 20 by means of an indicator arm 300projecting from a position transmitter 302 which, by means of a tube304, is connected to an air cylinder 306. Air cylinder 306 actuates apiston rod 308, the outwardly projecting end of which is pivotallyconnected with the rolling carriage structure of the cooling box 290.The upper free end of the indicator arm 300 engages one edge of theconveyor belt 20 so that any lateral movement of the conveyor belt 20actuates the position transmitter 302 so as to effect a correspondingmovement of the piston rod 308 to align the cooling box with the belt20. This aligning system is identical with and operates in the samemanner as the aligning system used for the steam boxes 174 and 278.Within the cooling box 290 there are mounted a plurality of transversepipes 310 which are connected to each other and to a source of coldwater (not shown). The pipes 310 are provided with a plurality of jetsor nozzles 312 located to direct a cold spray against the bottom of theconveyor belt 20 as illustrated in FIG. 12. Since the endless steel beltconveyor 20 is hot when entering the conditioner unit 42, the spray ofcold water onto the bottom of the belt 20 cools it. Spray water drops tothe bottom of the box 290 and flows out through a drain duct 314 leadingto a catching basin 316 which, in turn, is connected to a drain pipe 318leading out of the machine. Within the upper portion of the housing 288across the top of the belt conveyor 20 there are mounted a plurality ofsteam pipes 320 which are connected to a steam source (not shown) andprovided with a plurality of jets or nozzles 322 positioned to direct ablast of steam directly onto the sheet carried by the conveyor belt 20through the conditioner unit 42. The steam sprayed on the cooled sheetcondenses to raise its moisture content to a desired percentage to makeit pliable for further processing. In order to prevent any condensationwhich may form on the inner walls of housing 288 from dripping onto thesheet, the upper edges of the belt entrance and exit slot of the housing288 are provided with a steam pipe 324 which is hot enough to evaporateany condensation and prevent it from dropping onto the sheet to form wetspots. The bottom portion of housing 288 is provided with a suitablesuction duct 326 which is connected to a suction fan unit 328 whichsucks fresh air through an opening 330 in the top portion of housing 288and through the entire unit 42.

Insofar as is known, the hereabove described sheet conditioner is novel.It provides a very effective means of controlling final sheet moisture.Specific final moisture contents within the range of 10% to 40% basiscan be obtained. Control is obtained by adjusting the volume andtemperature of cold water sprayed on the belt bottom and by adjustingthe volume of steam and air drawn across the top of the sheet.

In operation, the steam, water and air flows are usually set at specificrates and control is exercised by thermostatic control of the watertemperature. This may be effected, for example, by using a recirculatingwater supply of constant volume (not shown) to which quantities of coldwater are added as required, displacing equivalent quantities of warmerwater in the system. An alternate means would be circulating the watersupply through a refrigerating heat exchanger as required. For Widevariations in desired final sheet moisture, as for example, between 12%and 25%, it is necessary to make adjustments to the flow rates of theair, water and steam. Once the level has been set the temperaturecontrol takes over, con trolling the sheet moisture between say 11.5%and 12.5% at the 12% level and between 24% and 26% at the 25% level.

An additional advantage of the herein provided conditioner over othermethods of conditioning tobacco sheet resides in the fact that itrequires a minimum of space and apparatus while providing a maximum ofuniformity and control.

In methods employed in the prior art as far as is known, the sheetcannot be conditioned on the same conveyor on which it is made. Instead,the sheet, after being made, is re-wet to a moisture considerably abovethat at which it is to be stored and used, then is doctored off andredried on another drying conveyor. The present invention eliminates theneed for this extra drying conveyor and accomplishes the same result ina relatively minor addition to space on the sheet making conveyor.

It will be understood that the use of this conditioner is not limited tothe conditioning of tobacco sheet but can be used to condition anymaterial being carried on an impervious, heat conductive belt.

The sheet emerges from the housing 288 with the desired moisture contentand, as shown in FIG. 1, is lifted off the conveyor belt 20 by means ofa conventional doctor knife 44 to be fed into the cutting unit 46 to becut or shredded as desired. After the sheet is lifted from the endlesssteel band conveyor belt 20, the latter is contacted by a plurality ofwipers 332 to assure its having a clean surface when it again reachesthe water applicator 30. A plow 334 which contacts the upper surface ofthe lower run of belt 20, is provided to clean it of any debris whichmay have been dropped on it.

Because the conveyor belt 20 is very long, it is important to controland counteract any lateral wandering of it. For this reason the machineis equipped with a continuous modulating tracking system to provide acorrective force in direct proportion to the amount of wandering of theconveyor belt 20. This tracking system, illustrated in FIGS. 13 to 16,consists of a position indicator arm 336 projecting from a positiontransmitter 338 and engaging with its upper free end one edge of theupper run of conveyor belt 20. The position transmitter 338, by means ofa tube 340, is connected to a source of compressed ai-r (not shown). Thetransmitter 338, by means of a tube 342, is also connected to a verticalair cylinder 344 and by means of tube 346 to air cylinder 348. Both aircylinders 346 and 348 are mounted on frame members of the machine andhave the piston rods 352 project downward through and into the bearingframe 350 as illustrated in FIGS. 15 and 16 of the drawing. From thelower free end of each piston rod 352 there is suspended a bearing block354 which slidably engages a pair of spaced vertical rails 356 securedto the frame 350. Each bearing block 354 is provided with a sphericalselfaligning bearing 358 which rotatably supports one end of a shaft 360to which is mounted a belt control roller 362 which engages the topsurface of the lower run of belt 20 as illustrated in FIGS. 1, 13 and14. Each bearing frame 350 is provided with an upper lug 364 and a lowerlug 366 both of which are slidingly engaged be tween the vertical tracks368 and the retainer bars 370. The track 368 is rigidly secured to themain structure of the machine and rotably supports a vertical spindle372 which is provided with a smooth upper portion 374 and a threadedlower portion 376. The threaded lower portion 376 of spindle 372 engageswith a. threaded bore 378 of the lower bearing frame lug 366 while theupper bearing frame lug 364 is just provided with a clearance hole 380to accommodate the smooth upper portion 374 of spindle 372. It isself-evident that by turning the spindle 372 the bearing frame 350 maybe raised or lowered to a desired position.

The tracking system operates in the following manner. When the conveyorbelt 20 runs true and even as illustrated in FIG. 13, the indicator arm336 is in a vertical position and causes the position transmitter 338 tokeep the air pressure in the vertical air cylinders 344 and 348 inbalance to lock the pistons within these cylinders and keep the controlroller 362 in a horizontal position. As soon as the belt 20 wanders offto one side as illustrated in FIG. 14, the indicator arm 336 will followthis movement and tilt to the side toward which the belt wanders. Thistilting the indicator arm 336 causes a shifting of valves within theposition transmitter 338 in such a manner as to permit the air pressureto reach only the air cylinder on the side of the belt towards which thebelt wanders while cutting off the air in the cylinder on the oppositeside. The piston within the cylinder to which air pressure is applied isforced downward and consequently the piston rod 352 and the bearingblock 354 that support the end of the shaft 360 carrying the controlroller 362 is moved downward causing the roller 362 to assume an angularposition. The increase of tension in one side of belt 20 forces the beltto wander back to its normal position. The tracking system is sodesigned so that movements of the vertical pistons within the aircylinders 344 and 348 are proportional to the horizontal swings of theindicator arm 336 and, consequently, the horizontal wandering of thebelt 20. When the belt 20 moves from its normal position it also movesthe indicator arm 336 which in turn causes one or the other of thevertical air cylinders to take corrective movement in proportion to thedeviation of the belt 20 from normality. Restoration to vertical of arm336 effects a decrease of the air pressure in that cylinder to which itwas applied for correction. Thus, when arm 336 reaches its normalvertical position, the air pressure in both vertical cylinders willagain be equal and the control roller 362 will resume its horizontalposition to evenly contact the belt 20. It will be apparent that thetracking arrangement herein described is useful in tracking any metallicband conveyor and hence should not be limited in application to its usein conjunction with any specific web forming conveyor construction.

While the invention for the purpose of providing a more appropriatelyspecific embodiment has been described in connection with forming sheettobacco it is not to be interpreted as so limited but can be used in themanufacture of any material which it is desired to make by gluing twolayers of dust together. Some examples of other uses are in themanufacture of (1) flexible wood sheet made by applying sawdust or woodflour with the two dust-feeders and a suitable adhesive with thebase-web applicator; (2) a flexible leather sheet made by applyingground leather particles with the two dustfeeders and a suitableadhesive with the base-web applicator; (3) food materials such asluncheon meat by applying ground meat with dust feeders and a suitableadhesive with the base-web applicator; (4) two sided abrasive sheets,and the like.

While we have shown our invention in the best form known to us, it willnevertheless be understood that this is purely exemplary and thatmodifications in the construction, arrangement, and combination of partsand the substitution of equivalents mechanically and otherwise, may bemade without departing from the spirit of the invention, except as itmay be limited in the appended claims.

What is claimed is:

1. An apparatus for forming continuous self-sustainable sheet materialcomprising a moving endless belt, means to deposit a thin film of liquidon said belt, at least one means to apply a layer of dry finely dividedmaterial to the wet belt, said means for applying the layer of drymaterial comprising in combination a knurled rotatable roller and arotatable cylindrical brush contacting said knurled roller, means forapplying said dry material supply to said knurled roller so thatmaterial picked up by said brush from said knurled roller is castdownward, said knurled roller and said brush being disposed transverselyabove said belt, at least one heating means for drying wet layers ofmaterial deposited on said belt, means to apply a layer binding materialonto said belt, said means for applying the layer binding materialcomprising a rotating feed drum, a rotating refuser drum disposed with alight clearance alongside said feed drum, said feed drum rotating withits upper surface moving downward toward said refuser drum and saidrefuser drum rotating with its upper surface moving upward away fromsaid feed drum, means to introduce liquid binding material between saiddrums, a rotating high speed cylindrical brush disposed across said beltand contacting said feed drum to cast a second layer of finely dividedmaterial downward onto said belt, and means to remove the integratedbound layers of material from said belt as a continuous self-supportableflexible sheet.

2. In an apparatus for forming tobacco sheets, a moving endless belt,means to deposit a thin film of liquid, on said belt, at least one meansto apply a layer of dry dust to the wet belt, said means to apply alayer of dry dust having a hopper, a tobacco dust supply to said hopper,a knurled and rotating roller extending into the bottom of said hopperwith a small clearance between said roller and the bottom of one side ofsaid hopper, and a rotating cylindrical brush contacting said knurledroller throwing dust carried from said hopper by said knurled rollerdownward, said knurled roller and said brush being disposed transverselyabove said belt, at least one heating means drying wet layers of tobaccodust on said belt, means to apply a layer of binding material onto saidbelt, said means to apply a layer of binding material having a rotatingfeed drum, a rotating refuser drum disposed with a slight clearancealongside said feed drum, said feed drum rotating with its upper surfacemoving downward toward said refuser drum and said refuser drum rotatingwith its upper surface moving upward away from said feed drum, means tointroduce liquid binding material between said drums and a rotating highspeed cylindrical brush disposed across said belt and contacting saidfeed drum to throw a second layer of tobacco downward onto said belt,and means to remove layers of (tobacco dust and binding) material fromsaid belt (as tobacco sheet).

3. The combination according to claim 2 comprising means to cool theunderside of said belt and means for moistening the layers on said belt,said cooling and moistening means being arranged in front of the meansto remove the layers from said belt.

4. An apparatus for forming tobacco sheet comprising, in combination,two pulleys, means to drive at least one of said pulleys, an endlessmetal belt disposed over said pulleys, means to deposit a thin film ofwater on said belt, first means to apply a layer of dry dust to the wetbelt, said first means having a hopper, a tobacco dust supply to saidhopper, a knurled and rotating roller extending with a small clearanceinto the bottom of said hopper and a rotating cylindrical brushcontacting said knurled roller to throw dust carried from said hopper bysaid knurled roller downward, said knurled roller and said brush beingdisposed across said belt, a suction funnel disposed across said beltdrawing up dust not held to said belt by the water film, first heatingmeans drying the wet layer of tobacco dust on said belt onto said driedtobacco layer, said means to apply a layer of binding material having arotating feed drum, a rotating refuser drum disposed with slightclearance alongside said feed drum, said feed drum rotating with itsupper portion moving downward toward said refuser drum, and said refuserdrum rotating with its upper portion moving upward away from said feeddrum, means to introduce liquid binding material between said drums, anda rotating cylindrical brush disposed across said belt and contactingsaid feed drum throwing binding material downward onto said belt, asecond means to apply a layer of dry dust to said belt similar to saidfirst means, second heating means drying the layers of tobacco dust andbinding material on said belt, a sheet conditioning apparatus raisingthe moisture content of the layers on said belt, said sheet conditioningapparatus having means to cool the underside of said belt and steamnozzles spraying the layers on said belt with steam, and means to removethe layers of tobacco dust and binding material from said belt astobacco sheet.

5. The combination according to claim 2 with the addition of means tosense lateral movements of said belt 13 and means to increase thetension in said belt on the side of'said belt towards which said belthas laterally moved.

6. In an apparatus for forming a continuous self-sustainable flexiblesheet product, the combination comprising a movable metal belt, means toapply a thin film of liquid to said belt, said means comprising, incombination, a roller having a resilient outer surface disposed acrosssaid belt and contacting said belt, drive means rotating said roller sothat the surface of said roller contacting said belt moves in theopposite direction from said belt, and a liquid reservoir above saidroller, said liquid reservoir having a rear seal extending across saidroller and contacting said roller preventing loss of liquid between saidrear seal and said roller, two end seals extending forward from saidrear seal, said end seals contacting the end of said roller to preventloss of liquid between said roller and between said end seals, askimming knife extending across the front of said roller between saidend seals, and means to adjustably position said skimming knife abovethe top surface of said roller to allow said roller to carry a thin filmof liquid from said reservoir to be deposited on said belt.

7. In a tobacco sheet forming apparatus having a moving metal belt,means to apply a thin film of water to said belt, said means comprising,in combination, a roller having a resilient outer surface disposedacross said belt and contacting said belt, drive means rotating saidroller so that the surface of said roller contacting said belt moves inthe opopsite direction from said belt, and a water reservoir above saidroller, said water reservoir having a rear seal extending across saidroller and contacting said roller preventing loss of water between saidrear seal and said roller, two end seals extending forward from saidrear seal, said end seals contacting the ends of said roller to preventloss of water between said roller and said end seals, a skimming knifeextending across the front of said roller between said end seals, andmeans to adjustably position said skimming knife above the top surfaceof said roller to allow said roller to carry a thin film of water fromsaid reservoir to be deposited on said belt.

8. In an apparatus for forming a continuous self-sustainable flexiblesheet product, the combination comprising a moveable belt, means toapply a layer of dry finely particulated material to said belt, saidmeans comprising, in combination, a hopper, a particulated materialsupply for said hopper, a roller extending into the bottom of saidhopper, said roller having a roughened surface and said roller extendingwith slight clearance from said roller, a cylindrical brush contactingsaid roller below the side of said hopper extending with a slightclearance from one side of said hopper, drive means for said cylindricalbrush rotating the side of said cylindrical brush contacting said rollerdownward throwing particulated material carried from said hopper by saidroller downward onto said belt.

9. In a tobacco sheet forming apparatus having a moving belt, means toapply a layer of dry dust to said belt, said means comprising, incombination, a hopper, a tobacco dust supply to said hopper, a rollerextending into the bottom of said hopper, said roller having a roughenedsurface and said roller extending with slight clearance from one side ofsaid hopper, drive means to rotate said roller toward the side of saidhopper extending with a slight clearance from said roller, a cylindricalbrush contacting said roller below the side of said hopper extendingwith a slight clearance from said roller, and drive means for saidcylindrical brush rotating the side of said cylindrical brush contactingsaid roller downward throwing dust carried from said hopper by saidroller downward onto said belt.

10. In a tobacco sheet forming apparatus having a moving belt, means toapply a thin layer of dry tobacco dust to said belt comprising, incombination, a hopper, a tobacco dust supply for said hopper, a knurledroller extending upward into said hopper and disposed across said belt,a front wall of said hopper disposed along one side of said roller,support means for said front wall allowing said front wall to beadjustably positioned with slight clearance from said roller, drivemeans for said roller rotating said roller toward said front wall, acylindrical brush disposed across said belt contacting said roller belowsaid front wall, and drive means rotating said cylindrical brush withthe portion of said cylindrical brush contacting said roller movingdownward to throw dust carried by said roller from said hopper downwardonto said belt.

11. The combination according to claim 8 with the addition of means toadjustably position said roller relative to said brush.

12. In an apparatus for forming a continuous self-sustaining flexiblesheet product the combination comprising a movable belt, means todeposit a layer of liquid bind ing material upon said belt, said meanscomprising, in combination, a feed roller disposed across said belt, arefuser roller disposed across said belt alongside said feed roller withslight clearance between said rollers, drive means for rotating saidrollers moving the portion of said feed roller adjacent to said refuserroller downward and moving the portion of said refuser roller adjacentto said drive roller upward, means flowing liquid binding material fromabove between said two rollers, a cylindrical brush contacting said feedroller, and drive means rotating said cylindrical brush throwing bindingmaterial from said feed roller onto said belt.

13. In a tobacco sheet forming apparatus having a moving belt, means todeposit a layer of liquid binding material upon said belt, said meanscomprising, in combination, a feed roller disposed across said belt, arefuser roller disposed across said belt alongside said feed roller withslight clearance between said rollers, drive means for rotating saidrollers moving the portion of said feed roller adjacent to said refuserroller downward and moving the portion of said refuser roller adjacentto said drive roller upward, means flowing liquid binding material fromabove between said two rollers, a cylindrical brush contacting said feedroller, and drive means rotating said cylindrical brush throwing bindingmaterial from said feed roller onto said belt.

14. The combination according to claim 11 wherein said refuser roller isadjustably positioned relative to said feed roller and said feed rolleris adjustably positioned relative to said cylindrical brush.

15. In a tobacco sheet forming apparatus having a first pulley, a secondpulley, means to drive at least one of said pulleys, and a horizontalmetal belt disposed about said pulleys, a tobacco sheet conditioningapparatus comprising, in combination, transverse tracks disposed beneathsaid belt, a water box of the same width as said belt slidably mountedbeneath said belt on said tracks, water pipes within said water box, asource of water connected to said pipes, nozzles in said water pipesdirecting a spray of water upward onto the under surface of said belt,means directing a spray of steam downward onto the tobacco sheet on saidcooled belt, drain means from said water box, means sensing lateralmotion of said belt, and means responsive to said means sensing lateralmotion of said belt keeping said water box directly beneath said belt.

16. In a tobacco sheet forming apparatus having a first pulley, a secondpulley, means to drive at least one of said pulleys, and a horizontalbelt disposed about said pulleys, transverse tracks disposed beneath arun of said belt, heating means of the same width as said belt slidablydisposed on said tracks beneath said belt, means sensing lateral motionof said belt, and means responsive to said means sensing lateral motionof said belt keeping said heating means directly below said belt.

(References on following page) UNITED STATES PATENTS Crean Dec. 31, 1901Dilg Feb. 3, 1914 5 Febles May 18, 1926 Febles Mar. 5, 1929 Brown et a1.Oct. 24, 1933 Manning Apr. 4, 1939 Garber Nov. 22, 1949 Kendall Sept.25, 1951 Seifried June 10, 1952 Bolton Apr. 26, 1955 Murphy Dec. 6, 1955Hungerford et a1 Feb. 14, 1956 Hungerford et a1. Feb. 14, 1956 AhlichMay 6, 1958 Buteux et al. Dec. 9, 1958

1. AN APPARATUS FOR FORMING CONTINUOUS SELF-SUSTAINABLE SHEET MATERIALCOMPRISING A MOVING ENDLESS BELT, MEANS TO DEPOSIT A THIN FILM OF LIQUIDON SAID BELT, AT LEAST ONE MEANS TO APPLY A LAYER OF DRY FINELY DIVIDEDMATERIAL TO THE WET BELT, SAID MEANS FOR APPLYING THE LAYER OF DRYMATERIAL COMPRISING IN COMBINATION A KNURLED ROTATABLE ROLLER AND AROTATABLE CYLINDRICAL BRUSH CONTACTING SAID KNURLED ROLLER, MEANS FORAPPLYING SAID DRY MATERIAL SUPPLY TO SAID KNURLED ROLLER SO THATMATERIAL PICKED UP BY SAID BRUSH FROM SAID KNURLED ROLLER IS CASTDOWNWARD, SAID KNURLED ROLLER AND SAID BRUSH BEING DISPOSED TRANSVERSELYABOVE SAID BELT, AT LEAST ONE HEATING MEANS FOR DRYING WET LAYERS OFMATERIAL DEPOSITED ON SAID BELT, MEANS TO APPLY A LAYER BINDING MATERIALONTO SAID BELT, SAID MEANS FOR APPLYING THE LAYER BINDING MATERIALCOMPRISING A ROTATING FEED DRUM, A ROTATING REFUSER DRUM DISPOSED WITH ALIGHT CLEARANCE ALONGSIDE SAID FEED DRUM, SAID FEED DRUM ROTATING WITHITS UPPER SURFACE MOVING DOWNWARD TOWARD SAID REFUSER DRUM AND SAIDREFUSER DRUM ROTATING WITH ITS UPPER SURFACE MOVING UPWARD AWAY FROMSAID FEED DRUM, MEANS TO INTRODUCE LIQUID BINDING MATERIAL BETWEEN SAIDDRUMS, A ROTATING HIGH SPEED CYLINDRICAL BRUSH DISPOSED ACROSS SAID BELTAND CONTACTING SAID FEED DRUM TO CAST A SECOND LAYER OF FINELY DIVIDEDMATERIAL DOWNWARD ONTO SAID BELT, AND MEANS TO REMOVE THE INTEGRATEDBOUND LAYERS OF MATERIAL FROM SAID BELT AS A CONTINUOUS SELF-SUPPORTABLEFLEXIBLE SHEET.